1. Field of the Invention
The present invention relates to a blood pressure measuring apparatus and particularly to improvements in such an apparatus which measures blood pressure based on pulse wave produced from a blood vessel of a living body.
2. Related Art Statement
Pulse wave is generally defined as pressure wave, or oscillation of the wall of a blood vessel, produced with heart beat of a living body and transmitted through the blood vessel. There has been proposed a device for determining blood pressure based on the pulse wave. The Inventors and others filed Japanese Pat. Application No. 62-130879 on May 27, 1987 in which they disclosed a pulse wave detecting device which is capable of determining maximum and minimum blood pressure based on the detected pulse wave. The device has (a) a housing detachably set on a body surface of a subject, (b) a pressure sensor accommodated in the housing such that the pressure sensor is opposed to the body surface when the housing is set on the body surface, the pressure sensor being pressed against the body surface so as to detect pulse wave produced from an arterial vessel of the subject, the pressure sensor generating pulse wave signal representing the detected pulse wave, (c) pressing means for pressing the pressure sensor against the body surface, and (d) a control circuit for determining blood pressure in the arterial vessel based on the pulse wave signal supplied from the pressure sensor. This device permits easier blood pressure measurement than a prior device using an inflatable cuff which occludes blood flow for blood pressure measurement as a result of compressing an upper arm of a subject. The above-indicated Japanese Pat. Application was laid open under Publication No. 63-293424 on Nov. 30, 1988.
However, the above-indicated pulse wave detecting device is not easy to handle or handy to carry because the pressing means and the control circuit are disposed apart from the housing and connected thereto via air piping and electric wiring, respectively. Furthermore, such air piping and/or electric wiring restricts activity of the subject to some extent.